1. Field of the Invention
This invention relates to structural resins and in particular to new polyimidazoles formed from the aromatic nucleophilic displacement reaction of novel di(hydroxyphenyl)imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds, whereby economically produced, high molecular weight polyimidazoles useful as adhesives, coatings, films, membranes, moldings, and composite matrices are obtained.
2. Description of the Related Art
Polyimidazoles (PI) are heterocyclic polymers which were synthesized by the reaction of a bis(phenyl-.alpha.-diketone) with an aromatic dialdehyde in the presence of ammonia as represented below: ##STR1## where Ar is a divalent aromatic radical such as ##STR2## R is a divalent aromatic radical which may be ##STR3##
The synthesis and characterization of PI was first described in 1967 [V. B. Krieg and G. Manecke, Die Makromolekulare Chemie, 108,210 (1967)]. The polymers were of relatively low molecular weight, and only a few physical properties were determined. PI prepared by the reactin of bis(phenyl-.alpha.-diketone) with aromatic dialdehydes in the presence of ammonia generally are of low molecular weight, presumably due to side reactions. Therefore, there are relatively few reports concerning the preparation and characterization of these materials.